The disclosure relates to an eccentric bearing having the features described below. The eccentric bearing according to the disclosure is intended, in particular, for an electrohydraulic piston pump assembly of a hydraulic brake system of a motor vehicle. Such pump assemblies are used for generating a hydraulic brake pressure for brake actuation in traction-controlled and/or power-assisted brake systems.
Known eccentric bearings have an eccentric shaft which is attached in one piece or in another way rigidly and eccentrically to a motor shaft of an electric motor or to an output shaft of a gear which can be driven by means of the electric motor. The eccentric shaft has arranged on it a rolling bearing with a bearing ring concentrically surrounding the eccentric shaft and with rolling bodies which are arranged in a gap between the eccentric shaft and the bearing ring around the shaft, usually, but not necessarily, equidistantly. The rolling bodies are normally rollers or needles, although they may also be other rolling bodies, for example balls. The bearing ring may be interpreted as an outer ring, and an inner ring may be present, for example pressed onto the eccentric shaft. However, an inner ring is not necessary, and the rolling bodies may also roll directly on the eccentric shaft. One or more pump pistons of the pump piston assembly bear with their end faces on the bearing ring on the outside. The pump pistons are pressed, for example by means of springs, into bearing contact against the bearing ring from outside.
During rotary drive, the eccentric shaft, because of its eccentricity, executes movement on a circular path and at the same time rotates about itself. On account of the movement of the eccentric shaft on the circular path, the bearing ring also moves on a or on the same circular path and thereby drives the pump piston, bearing against it on the outside, in the desired lifting movement, in order to convey brake fluid or fluid in general by alternate suction intake and displacement, as is known from piston pumps. On account of its rolling mounting, the bearing ring does not corotate with the eccentric shaft.
In electrohydraulic piston pump assemblies for hydraulic brake systems of motor vehicles, the eccentric bearings convert a rotational movement of an electric motor or of an output shaft of a gear into a lifting movement for driving the pump pistons.